GB2602870A - Concrete formulation and products manufactured therefrom - Google Patents

Abstract

A concrete formulation containing a binder, which may or may not be cementitious, and at least one aggregate. The aggregate includes at least two plastic materials of the following types, which may be sourced from recycled or reprocessed waste: polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), nylon, polylactic acid (PLA), rubber, or their copolymers. The plastic may be processed to form granulated particles such as pellets, chips (fig. 2), flakes (fig. 3), or a mixture of these, and may be used to replace up to 100% of any conventional, coarse aggregate within the concrete. The formulation may also be used to produce ready mix concrete, concrete masonry units (CMUs), interlocking concrete blocks, and other similar products. The CMU may contain between 1 and 19% by weight of any aggregate content as plastic. The use of plastic as an aggregate is intended to lower the environmental impact of the concrete and subsequent products.

Description

Concrete Formulation and Products Manufactured Therefrom The present invention relates to an improved, more environmentally friendly and sustainable concrete formulation and products made from the same.

Conventional concrete is a composite material, made up of a mix of aggregate and a binder. Aggregates are typically gravel, stones, rocks, and sand of various sizes. The binder is typically cementitious, for example Portland cement, or non-cementitious such as bitumen or asphalt or other cement free binders. The binder holds or binds the matrix together. Binders and aggregates are mixed with water to form the concrete. The properties and formulations of binders and the types of aggregate used determine the type of concrete produced, which is selected to suit the application for the material. These variables determine strength, density, as well as chemical and thermal resistance of the finished product.

The production process of making concrete includes mixing together the components making up the formulation; primarily water, the aggregate, cement and/or other binder, and any additives. There are two main types of production; ready mix plants and central mix plants. A ready-mix plant mixes all the components except water, while a central mix plant mixes all the components including water. Obviously a central-mix plant must be located close to the site of use as hydration or curing begins at the plant with the addition of the water.

Conventionally concrete is prepared as a viscous fluid, which is poured into forms 25 or containers to give the desired shape. Alternatively, concrete can be mixed into dryer, less fluid forms and to manufacture precast concrete products, for example pressed into precast concrete masonry units or blocks.

Concrete is an abundant material with billions of cubic metres being produced every 30 year. As such, concrete production has a high environmental impact.

It is therefore an aim of the present invention to provide a concrete formulation that address or improves the environmental impact of concrete.

It is a further aim of the present invention to produce formed concrete products, such as blocks, that have a lower impact on the environment.

In a first aspect of the invention there is provided a concrete formulation, said formulation including at least one aggregate and a binder, characterised in that the aggregate includes plastics material said plastics material including two or more of the following; Poly (ethylene); Poly(ethylene terephthalate); - Poly(propylene); - Poly(styrene); - Poly (vinyl chloride); -Nylons; - Poly(lactic acid); - Rubbers; and - copolymers of the above.

In a preferred embodiment of the invention the concrete formulation is suitable for ready mix concrete and CIVILTs.

In a preferred embodiment at least part of the bulk or coarse aggregate of the concrete formulation comprises at least two or more of the following plastics; -Polyethylene (PE); - Polyethylene terephthalate (PET); - Polypropylene _ o_ypropylene (PP); - Polystyrene (PS); Polyvinyl chloride (PVC); Nylons; Polylactic acid (PIA); - Rubbers; and - copolymers of the above.

In a preferred embodiment of the invention the plastics material is recycled and/or recovered plastics material. Typically the plastics material is recovered waste plastics material.

In one embodiment the rubbers include silicone rubbers. In one embodiment the rubbers include natural rubbers or latexes.

In a preferred embodiment of the invention the binder is a cementifous binder or cement. Preferably the cement is Portland cement.

In one embodiment the binder includes, or comprises, a non-cementitious binder. 5 Typically the binder includes, or comprises, a bituminous binder or cement-free binders.

In one embodiment the aggregate includes coarse aggregate and/or fine aggregate.

Typically coarse aggregates include limestone pieces, gravel and/or granite pieces. Further typically other coarse aggregates include clays, perlite, pumice, shale, scoria, slate, expanded clays, vermiculite, and the like, and mixtures of the aforementioned aggregates.

Typically fine aggregates include sand, marine sands, limestone dusts, or other fine aggregate materials of a specific size and/or mixture of sizes.

Typically the plastics material is packaging waste. Further typically the waste plastics material is in the form of any one or any combination of pots, tubs and trays, plastic banding, plastic bottles, IBCs, plastic pallets, and shredded, crushed granulated or pulverised plastic packaging plastic. The skilled person will appreciate that other waste plastics material could be used and is not limited to packaging waste.

In one embodiment plastic waste material includes, but is not limited to, plastic packaging waste. Further typically the waste plastics material is in the form of any one or any combination of pots, tubs and trays, plastic banding, plastic bottles, IBCs, plastic pallets and shredded, crushed, granulated, or pulverised plastic packaging plastic.

Typically the plastics include any combination of polystyrene (PS), low density polyethylene DPE), high density polyethylene (HDPE), other polyethylenes (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyamides (including Nylons and other related polymers), and/or polyesters and/or co-polymers thereof Typically the plastic waste material is sourced from waste reprocessing sites.

Tn one embodiment the plastic waste is processed into any one or any combination of pellet, chip, or flake shape.

Tn a further embodiment the plastic waste includes granules, grains, strings, rods, balls, or ellipsoids, and/or the like.

Further typically the plastics materials conform to recycling standards. The following standards are currendy relevant in the UK: * BS EN 15342, Plastics Recycled Plastics Characterization of polystyrene (PS) rccyclates * BS EN 15343, Plastics Recycled Plastics -Plastics recycling traceability and assessment of conformity and recycled content * BS EN 15344, Plastics -Recycled Plastics -Characterisation of Polyethylene (PE) recyclates * BS EN 15345, Plastics Recycled Plastics Plastics recyclate characterisation of (PP) recyclates * BS EN 15346, Plastics -Recycled plastics -Characterisation of poly(vinyl chloride) (PVC) recyclates * BS EN 15347, Plastics -Recycled Plastics -Characterisation of plastics wastes * BS EN 15348, Plastics -Recycled plastics -Characterization of poly(ethylene terephthalate) (PET) recyclates * CEN(TR 15353, Plastics Recycled plastics Guidelines for the development of standards for recycled plastics These standards may be superseded in the future.

Typically by following the materials and methods of the present invention, production of the concrete generates a lower environmental impact than alternative recovery options by using the plastic waste as a substitute for raw materials such as 30 gravel/limestone/granite and/or the like.

Typically, the plastics material includes one or more polymers. Further typically the plastics material replaces at least some of the conventional aggregate material such as gravel, stone, rock, limestone, sand and/or the like.

In one embodiment the plastics material is a mix of polymers.

Tn a preferred embodiment the plastics material is used as a replacement for coarse aggregate in the concrete formulation. Typically the plastics materials may replace up to 10t) % of the coarse aggregate in concrete. Preferably the plastics material would form 1-75% by weight (1-85% by volume) of the coarse aggregate.

In a preferred embodiment of the invention the plastics material includes polymer 5 pieces a minimum of 10 microns in diameter. Typically the size is substantially 1-20 mm. Preferably the size is 4-20 mm.

In a preferred embodiment the ready mix formulation includes plastics material of a size 4-20 mm in diameter and for products made therefrom.

In one embodiment the plastics material are pellet, chip, flake shapes, or a mixture thereof.

In one embodiment the plastics material also includes one or more other shapes such as grains, strings, rods, balls, ellipsoids, irregular polygons.

In one embodiment the plastics material is granulated to a size of substantially 1-25 mm diameter or longest dimension. Preferably the plastics material has a diameter of 1-20 mm. Further preferably the mean size is equal to or less than 20 mm in 20 diameter.

In one embodiment at least some of the plastics material is in the form of pellets. Typically the pellets are substantially cylindrical in shape. Further typically the pellets are formed via extrusion through a die.

In one embodiment the pellets are between 2.0 rru-n and 4.6 mm in their longest dimension. Typically the mean length is 3.3 mm with a variance of 0.5 mm. Further typically the pellets are often not perfect cylinders and vary in diameter around the cylinder.

In one embodiment the diameter of the pellets is usually between 1.0 mm and 4.5 mm. Typically the mean diameter is 2.6 mm with a variance of 0.6 mm.

In one embodiment at least some of the plastics material is in the form of chips. 35 Typically the chip shaped plastics are typically three-dimensional pieces of plastic with rough surfaces. Further typically the chip material possess one longer axis with two shorter axes.

In one embodiment the chip material resembles coarse limestone aggregate in texture. Typically the chipped plastics material is produced through a shredding and/or grinding process.

Typically the chips arc between 3.0 mm and 19 mm in their longest dimension. Further typically the chips have a mean length of substantially 8.4 mm with a variance of 3.3 mm.

Typically the two shorter dimensions of the chip shaped plastics are between 16mm and 0.5 mm in length, with a mean length of 5.0 mm with a variance of 2.6 mm.

In one embodiment the plastics material includes flake shaped plastics. Typically the flakes are substantially two-dimensional with each piece being significantly 15 thinner in one dimension than the others giving the flaky appearance.

In one embodiment the thickness of the flakes is usually between 0.05 mm and 4.2 mm. Typically the mean thickness is 0.9 mm with a variance of 0.5 mm. Further typically the length varied between 1.0 mm and 30 mm.

In one embodiment the flake mean length is substantially 8 mm and a variance of 3.9 mm.

In one embodiment the flake width is between 1.0 mm and 10 mm. Typically the 25 mean length is substantially 4.8 mm and a variance of 2.1 mm.

In one embodiment the plastics material forms around 1-75 ",710 by weight of the aggregate material. Typically the non-plastics aggregate is conventional aggregate such as gravel, stone, limestone and/or sand.

In one embodiment the plastics material forms around 5-20 % by weight of the aggregate material. Typically the plastics material forms around 5-20 '1/4) by weight of the coarse aggregate material.

In one embodiment the plastics material forms substantially 5, 11, 15, 19, 30, 50, or 75% aggregate replacement.

In one embodiment the plastics material forms around 5-19 by weight of the coarse aggregate material.

In one embodiment ready mix concrete is poured into moulds, trenches and/or 5 formed into concrete products. Typically the formulation includes substantially 9, 12 or 15 % weight of the coarse aggregate which is plastics material. Further typically such products include interlocking blocks.

In one embodiment interlocking blocks poured or formed from ready mix concrete 10 formulation includes substantially 9, 12 or 15 % weight of the aggregate which is plastics material. Typically the ready mix concrete formulation includes substantially 9, 12 or 15 % weight of the coarse aggregate which is plastics material.

In one embodiment the plastics material is further processed after output from a 15 waste reprocessing site. Typically further processing includes heating or warming up to the plastics' glass transition temperature prior to inclusion in concrete mixes.

In one embodiment further processing of the plastics material includes agitating and/or grinding to give a more rough and uneven shape prior to inclusion in 20 concrete mixes, washing steps, and any other processing or combination of processes to improve the plastic quality as an aggregate for use in concrete.

Concrete mixes containing plastics material may also include admixtures including but not exclusive to plasticizers, curing speed agents, and additives to alter 25 workability.

In one embodiment the formulation is mixed with or includes water.

In one embodiment the formulation is provided as ready-mix concrete. In an 30 alternative embodiment one or more components of the formulation are provided for mixing on site. Typically site mixing occurs at building sites and similar.

In one embodiment for products made from ready mix concrete, the processed plastic waste would form 2-19% by weight of the total mass of the coarse aggregates.

In one embodiment the formulation is used to produce interlocking concrete blocks.

In a preferred embodiment the concrete formulation is used for ready mix concrete. Typically the ready mix can be used to form interlocking blocks.

In one embodiment the concrete produced or manufactured to this formulation is used as back filling concrete.

In one embodiment the concrete produced or manufactured to this formulation is formed into curbs, bollards, lintels, and/or the like.

In a second aspect of the invention there is provided a method of preparing ready mix concrete, said method including the steps of replacing at least some of the aggregate with a combination of plastics material selected from two or more of polystyrene (PS), low density polyethylene DPE), high density polyethylene (HDPE), other polyethylenes (PE), polypropylene (PP), polyvinyl chloride (PVC), 15 polyethylene terephthalate (PET), polyamides (including Nylons and other related polymers), and/or polyesters and/or co-polymers thereof.

In one embodiment coarse and fine aggregates are mixed prior to adding half of the total volume of water intended to be in the final mix. Typically the cement is then 20 mixed in, followed by the remaining volume of water.

In one embodiment all dry materials, aggregates, plastics and/or binder are added to a mixer before the addition of water. Typically the dry materials are dispensed from hoppers.

Additionally, the plastic materials described here may be further processed after output from a waste reprocessing plant by way of any one or combination of the following; warming up to the plastics' glass transition temperature prior to inclusion in concrete mixes, warming and agitating to give a more rough and uneven shape prior to inclusion in concrete mixes, washing steps, and/or any other processing or combination of processes to improve the plastic quality as an aggregate for use in concrete.

Concrete mixes containing plastics may also include admixtures including but not exclusive to plasticizers, curing speed agents, and additives to alter workability.

Tn a third aspect of the invention there is provided a concrete masonry unit (CMU), wherein said CMU includes substantially 1-19% by mass of the aggregate material is plastics material.

Typically 1-3011/ by volume of the aggregate material is plastics material.

typically the CMU contains a combination of two or more of the following plastics; Polyethylene (PE); Polyethylene terephthalate (1)V1); - Polypropylene (PP); Polystyrene (PS); Polyvinyl chloride (PVC); NOons; Polylactic acid (PLA); - Rubbers; and copolymers of the above.

Preferably the ClVILT contains at least two of the following plastics; polystyrene (PS), low density polyethylene DPE), high density polyethylene (HDPL), other polyethylenes (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (P1 polyamides (including Nylons and other related polymers), and/or polyesters and/or co-polymers thereof Typically the plastics material forms substantially 3, 6, 9, 12, 19% by mass (5, 10, 15, 25 20, or 30 % by volume) of the aggregate of the mix forming the CIVEL.

Preferably the size of the plastics material is 2-10 mm diameter for semi-dry concrete mixes from which CMUs and other related products are prepared from.

In one embodiment the plastics material can replace coarse aggregates up to 19% by mass.

Specific embodiments of the invention are now described with reference to the following figures, wherein: Figure 1 shows an image of the pellet shaped processed waste plastic in accordance with one embodiment of the invention; Figure 2 shows an image of the chip shaped processed waste plastic in accordance with one embodiment of the invention; Figure 3 shows an image of the flake shaped processed waste plastic in accordance with one embodiment of the invention; Figure 4 shows an image of plastic mix 1 used in concrete mixes; Figure 5 is a plot of plastic mix 1 graded through a series of sieves; Figure 6 shows an image of plastic mix 2 used in concrete mixes; Figure 7 is a plot of plastic mix 2 graded through a series of sieves; Figure 8 shows an image of plastic mix 3 used in the concrete mixes; Figure 9 is a plot of plastic mix 3 graded through a series of sieves; figure 10 is a plot showing compressive strength of ready-mix concrete mixes; ready-mix concrete ready-mix concrete ready-mix concrete ready-mix concrete ready-mix concrete ready-mix concrete Figure 11 is a plot showing compressive strength of CC200 mixes; Figure 12 is a plot showing compressive strength of CC250 15 mixes; Figure 13 is a plot showing compressive strength of CC300 mixes; Figure 14 is a plot showing compressive strength of CC350 mixes; Figure 15 is a plot showing compressive strength of CC400 mixes; Figure 16 is a plot showing compressive strength of CC450 mixes; Figure 17 is a plot showing density of ready-mix concrete mixes; Figure 18 is a plot showing compressive strength of CC250 ready-mix concrete mixes; Figure 19 is a plot showing-density of ready-mix concrete mixes; Figure 20 is a plot showing compressive strength of CC250 ready-mix concrete mixes; Figure 21 is a plot comparing compressive strength of low slump mix vs. high slump mix; Figure 22 is a plot showing compressive strength of ready-mix concrete; Figure 23 is a plot showing density of ready-mix concrete; Figure 24 is a plot showing compressive strength of ready-mix concrete; Figure 25 is a plot showing density of ready-mix concrete; Figure 26 is a plot showing compressive strengths of ready-mix concrete mixes; Figure 27 is a plot showing compressive strengths for Hock mix A with plastic mixes 1, 2 and 3; Figure 28 is a plot showing compressive strength against curing time for block mix B with plastic mixes 1,2 and 3; I figure 29 is a plot showing compressive strength against curing time for all 15% plastic by volume replacements; Figure 30 is a plot showing the densities of all five block mixes up to 15% replacement by volume; Figure 31 is a plot showing the density of block mix A with plastic mix 2; Figure 32 is a plot showing the strength of block design A with increasing curing time for plastic mix 2; Figure 33 is a plot showing the CAW strength at 7 days and 28 days For block mix A containing plastic mix 2; Figure 34 is a diagram of the thermal testing experimental set up; Figure 35 is a plot of the temperature difference against distance on the block away from the heat plate for B3b-001; Figure 36 is a plot showing (dT/dx) against plastic replacement for block mix A; Figure 37 is a plot showing (dT/dx) for plastic replacements of 5% and 15% by volume for block mix B; Figure 38 is a plot showing (dT/dx) against density for block mix A; and Figure 39 is a plot showing (dlldx) against density for block mix B Product details The invention relates to concrete products containing plastic materials as a (partial) 25 replacement of coarse aggregates in the mix from which the concrete product is prepared from.

Described herein are ready-mix concrete mixes containing plastics, which are typically described as wet mixes, and can be used for backfilling, pouring into moulds 30 to form interlocking blocks, pouring into moulds to form lintels, pouring to form foundations, footpaths, and other civil engineering projects, among other uses.

Additionally, we describe semi-dry concrete mixes containing plastics which are used to prepare (Allis, breeze blocks, and related other products.

These concrete products containing plastic materials as a(partial) replacement of coarse aggregates are beneficial to the environment by removing plastic waste from polluting the environment through landfill, litter, and burning for refuse-derived fuel-based power among others.

Materials Cement is typically Portland cement; however other binders may be used such as bitumen-based binders or other cement-free binders.

Coarse aggregates used in concrete are often comprised of limestone pieces of a specific size or a mixture of sizes, or specifically sized or mixtures of different sized gravel or granite pieces. Other coarse aggregates include clays, perlite, pumice, shale, scoria, slate, expanded clays, vermiculite, and the like, and mixtures of the aforementioned aggregates.

Pine aggregates used in concrete often comprise of sand, marine sands, limestone dusts, or other fine aggregate materials of a specific size or mixture of sizes.

The plastics material is used as a replacement coarse aggregate. The plastics material may replace up to 100 % of the coarse aggregate in concrete. Preferably the plastics material would form 1-75"A by weight (1-85% by volume) of the coarse aggregate.

For ready-mix concrete and products made therefrom, preferably the plastics material would form 2-19% by weight of the total mass of the coarse aggregates, although the plastic replacement of the coarse aggregate can be used in ready-mix concrete up to 75%.

For concrete masonry units (CMUs), preferably the plastics material would form 119% by weight (1-30% by volume) of the total mass of the coarse aggregates.

The plastics material can be plastic waste. Plastic waste typically refers to, but is not limited to, plastic packaging waste. Further typically the waste plastics material is in the form of any one or any combination of pots, tubs and trays, plastic banding, plastic bottles, IBCs, plastic pallets and shredded, crushed, granulated, or pulverised plastic packaging plastic.

Typically, the plastics include one or any combination of polystyrene (PS), low density polyethylene (LDPE), high density polyethylene (prrwq other polyethylenes (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyamidcs (including Nylons and other related polymers), and/or polyesters and/or co-polymers thereof, although this list is not exhaustive.

The plastic is waste would typically be sourced from waste reprocessing sites. The 5 plastic waste may be a pellet, chip, or flake shape, a mixture of the forementioned, or other shapes not specified such as grains, strings, rods, balls, or ellipsoids, or any other shape.

For use in any concrete, ideally the plastic waste materials should be processed to a 10 minimum of 10 micrometrcs in diameter. Typically, the size is substantially 1 -20mm.

Preferably the size is 4-20 mm for use in ready-mix concretes and products made therefrom. Preferably the size is 2-10 mm for semi-dry concrete mixes from which CMUs and other related products are prepared from.

Additionally, the plastic materials described here may be further processed after output from a waste reprocessing site by way of warming up to the plastics' glass transition temperature prior to inclusion in concrete mixes, warming and agitating to give a more rough and uneven shape prior to inclusion in concrete mixes, washing steps, and any other processing or combination of processes to improve the plastic quality as an aggregate for use in concrete.

Concrete mixes containing plastics may also include admixtures including but not exclusive to plasticizers, curing speed agents, and additives to alter workability.

One method of making concrete mixes is to mix the coarse and fine aggregates, prior to adding half of the total volume of water intended to be in the final mix. The cement is then mixed in, followed by the remaining volume of water.

A more common method of making concrete mixes is to combine the coarse and 30 fine aggregates, along with the cement, prior to adding the total volume of water required by the mix design. This is more typical of how concrete is prepared at ready-mix plants.

Experimental Methods and Data For both ready-mix concrete trials and CML: block) trials, three different plastic mixtures were used: * Plastic Mix 1 -Chip/ Flake Mix * Plastic Mix 2 -Pellets Mix * Plastic Mix 3 -Fine Flaky Mix The plastic mixes were typical of outputs from waste recycling facilities; however S these typical outputs are not an exhaustive list of possible outputs.

Plastic dimensions, shapes, and size distribution General shape identification In general, waste plastics are usually pellet, chip, or flake shapes, or a mixture thereof The plastic outputs from waste re-processors are typically one of or a mixture of these shapes. These shape descriptions are not exhaustive, as the plastic waste may also have a variety of other shapes such as grains, strings, rods, balls, or ellipsoids, or any other shape.

Actual plastic waste outputs are also described in this section and are referred to as plastic mix 1,2, and 3. These plastic mixes were used in the ready-mix concrete mixes and the semi-dry block concrete mixes described in the later sections.

Pellet Shape: The pellet shaped plastics are approximately cylindrical in shape, typically formed via extrusion through a die. The pellets are usually between 2.0 mm and 4.6 mm in their longest dimension, with a mean length of 3.3 mm with a variance of 0.50 mm. The pellets are often not perfect cylinders and vary in diameter around the cylinder. The diameter of the pellets is usually between 1.0 mm and 4.5 mm, with a mean diameter of 2.6 mm with a variance of 0.60 mm Chip Shape: The chip shaped plastics are typically three-dimensional pieces of reprocessed waste plastic with rough surfaces. They typically possess one longer axis with two shorter axes. They often resemble coarse limestone aggregate in texture and are often produced through a shredding and grinding process. The chips are usually between 3.0 mm and 19 mm in their longest dimension, with a mean length of 8.4 mm with a variance of 3.3 mm. The two shorter dimensions are usually between 16 mm and 0.5 mm in length, with a mean length of 5.0 mm with a variance of 2.6 mm.

Flake Shape: The flake shaped plastics are typically more two-dimensional with each piece being much thinner in one dimension than the others giving the flaky appearance. The thickness of the flakes is usually between 0.05 mm and 4.2 mm, with a mean thickness of 0.9 mm with a variance of 0.5 mm. The length varied between 1.11) mm and 30 mm, with a mean length of 8.2 mm and a variance of 3.9 mm. The width varied between 1.0 mm and 10 mm, with a mean length of 4.8 mm and a variance of 2.1 mm.

Plastic Mix 1 Plastic mix 1 comprised of a mixture of chip-shaped and flake-shaped waste plastics. The ratio of flake to chip was approximately 1:4.

The chip pieces varied in their longest dimension between 0.5 mm and 19 mm, with a mean length of 8.6 mm with a variance of 3.3 mm. The other dimensions varied in length between 0.5 mm and 16 mm, with a mean of 8.6 mm (variance of 2.9 mm). The thickness of the flakes varied between 0.5 mm and 2.0 mm, with a mean thickness of 0.8 mm with a variance of 0.3 mm. The length varied between 4.0 mm and 21 mm, with a mean length of 10 mm and a valiance of 3.8 mm. The width varied between 2.0 mm and 10 mm, with a mean length of 5.6 mm and a variance of 2.2 mm.

Plastic mix 1 was graded through a series of sieves with descending aperture sizes to determine the size distribution of the plastic pieces comprising the mixture. Only 1 % of the total mass of the plastic mix passed through the 2 mt-n sieve. The majority of the plastic mix was retained on the 5 mm sieve demonstrating that the majority of the plastic pieces were between 5.0 mm and 8.0 mm in size.

Table 1 -Plastic mix 1 ske grading thromgb sieves with descending aperture.sizes.

". . . . ^:%% . . . . . . . . 16.0 0.0% 0.0% 100.1)(l/0 10.0 0.5% 0.5% 99.5% 8.0 118% 143% 85.7% 5.0 57.4% 71.7% 28.3'0 4.0 12.7°0 84.3°0 15.7% 2.0 14.7% 99.0% 1.0% Pa ii 1 0% 1000/0 0. 0°4 Plastic Mix 2 Plastic mix 2 comprised of pellet-shaped pieces Inc pellet-shaped plastics were approximately cylindrical in shape. The pellets were between 2.0 mm and 4.5 mm in their longest dimension, with a mean length of 3.1 mm with a variance of 0.4 mm. The pellets were not all perfect cylinders and varied in diameter around the cylinder. The diameter of the pellets was usually between 1.0 mm and 4.0 mm, with a mean diameter of 2.7 mm with a variance of 0.5 mm.

Plastic mix 2 was graded through a series of sieves with descending aperture sizes to determine the size distribution of the plastic pieces comprising the mixture. 1.ess than 1 ":0 of the total mass of the plastic mix passed through the 2 mm sieve. 'llhe majority of the plastic mix was retained on the 2 mm sieve demonstrating that the * rity of the plasticwere between 2.0 mm and 4.0 mm in size. 7

Plastic Mix 3 Plastic mix 3 was a mixture of different sized flakes of varied thickness.

The flakes comprising plastic mix 3 varied in thickness between 0.04 mm and 4.2 mm, with a mean thickness of 0.9 mm and a variance of 0.7 mm. The length of the flakes varied between 4 mm and 30 mm, with a mean length of 9.0 mm and variance of 3.7 mm. il'he width of the flakes varied between 1.0 mm and 10 mm, with a mean width of 5.4 mm and variance of 1.9 mm.

Plastic mix 3 was graded through a series of sieves with descending aperture sizes to determine the size distribution of the plastic pieces comprising the mixture. 24.1 (I/Ii 16.0 10.0 8.0 5.0 4.0 2.0 Pan ni-:7/1,loe klasfic mix 0)::))00 ( 100.0' 0 0.(1°0 ().()° 0 0.0 /0 0.2°0 13 0 0°0 0.2'0 0.5°0 99.2°0 100.0°70 100.0°0 98.6°0 100.0n 'n 0.8° 99.8' () 99.5°0 0.8°,10 0.0°,10 of the total mass of the plastic mix passed through the 2 mm sieve. As this was a significant quantity, any finer pieces of plastic below 2 mm were removed from the plastic mix prior to use in concrete mixes. The plastic pieces below 4 mm in plastic mix 3 were not used in any concrete mix.

The majority of the plastic mix was retained on the 5 mm sieve (35.0 %) however 18.2 (1/b and 24.9 % of the total mass of plastic mix 3 was retaining on the 4 0 mm and 2.0 mm sieves respectively. From this, it was determined that most of the plastic pieces comprising plastic mix 3 were between 2.0 mm and 8.0 mm in size.

Table 3 -Pk; st/r i\ 3 ke gradeleg through 31CreS *z5.5.:". ;5.55 * 5.

16.0 0.0 10.0 0.1°o 0.5% 35.01% 18..2'/0 24.9(1/1) l00.0' Plastic Mixtures Composition A representative sample of each plastic mix was separated from the bulk at random, and the total mass of the sample recorded. The sample was carefully separated by eye into different components and the mass of each component fraction was recorded. The component fractions were then identified by Fourier Transform Infra-red spectroscopy (FTIR), using an ATR FTIR spectrometer (iS5 IFC) from Thermo Fisher Scientific.

Plastic Mix 1 The majority of plastic mix 1 was poly(vinyl chloride). The remainder of the mix was a mixture of silicone rubber, various copolymers, and poly(styrene), among others.

Table 4 -The polymer colt/pone/Its (.1-pkiciic azi..%; /. !

! ! ! ! Polv(\-in-vl chloride) 91,4° 8.0 5.0 4.0 2.0 Pan 0.1°0 0..6°0 35.6'0 53...7()/() 78.6% 100.0° ii 99.90/0 99.4(11} 64.4% 46.3'0 21.4°/0 0 01)/0 Plastic Mix 2 Plastic mix 2 was mostly poly(ethylene).

Table 5 -The polpiier components of'pla.stic lila' 2.

EEPEolv(ethvleile)E:E:EEEEE:E:EEEEEE:E:EEEEEE:E:E: EEEEEEEEEEEEEEEEEEEEEEEEEEEEEE E50 E6°/0: EEEEEEEEEEEEEEE EEEEEEE: Poli..:(sty-renc-co-acrirlonitrile-co- 28.3°710 butadiene) Nylon 66 20.91⁄4 Poly(propylcnc) 0.1% Plastic Mix 3 Plastic mix 3 comprised a mixture of mostly poly(ethylene), poly(propylene), and poly(ethylene terephthalate) among others. There were also miscellaneous non-components which were removed from the plastic mix by careful sorting prior to use in concrete mixes. Additionally, it was noted that the miscellaneous fraction made up 18.3% of the total mass of the mix. This percentage is relatively high as the fraction contained glass and metals which are typically heavier than the plastic fractions as glass and metals are more dense materials than the polymers.

Silicone Rubber 2.9% Poly(stvrene) 1.3% Alkyd Resin 0.1% 0.6% Other mixed plastics 1)oly(ethylene:propylen:diene) 2 0°0 Poly(ethilene tercphthalate) Poly(vins,4 propionate:acrylate) Poly(ethylene) l'olvcarbonate Pcils-(styrene-butadiene-styrene) (block polymer) Pc Ay (propylene) 0.1% 0.4% Table 6 -The - . . . . . oiy_mer :1P01y.(Ct11)..1C111c) 53.81 Polv(propylene) 14.37% Poly(eth)lene te phthalate) 12.96)/0 Polv(ethylenc:propylencdiene) 0.17% Poly(butadiene) Other mixed plastics 0.35')/0 Miscellaneous (non-plastics including metal, paper, and 18.30' i) glass) Plastic Densities and Water Absorption The bulk density of the plastic mixtures is a ratio of the mass of the material to the volume of that material including any voids, both in the material itself and due to 5 imperfect stacking of the material particles in that volume.

The bulk density was determined by packing the plastic sample into a 3L density bucket and recording the mass. The plastic was compacted in by repeated rodding over three layers. The mass of the plastic is then divided by the volume of the bucket 10 to give the compacted bulk density.

The absolute density of the plastic mixtures was determined by pycnometry. Pycnometry is used to give an absolute volume of a sample accounting for pores in the sample material. The sample mass is then divided by the absolute volume to give the absolute density. Pycnometry was carried out using a Micromeritic Accupyc II 1340.

Water absorption is presented as a percentage change in the mass of the plastic material following submersion in water for 24 hours. Alternatively, this could be defined as the ratio of the mass of water absorbed by the plastic material over a 24-hour period over the dry mass of the plastic material. The water absorption was determined by taking a representative sample of each plastic from the bulk and soaking it in water for 24 hours. The mass was then recorded, and the plastic sample dried, and the dry mass recorded.

Plastic Mix 1 Table 7 The density and water absorption propettles of fiki.ctic /in.\ 1.

Compacted Bulk D / kg ompacte Bu Density m3 756 Absolute Density / kg m Water Absorption / % 1521).7+().6 0.96 Plastic Mix 2 Table 8-The density and water alrsorption properites f plastic;nix. 2.

Compacted Bulk Density / kg m" 771 Absolute Density / kg m" 1172.2±0.6 Water Absorption / "A) 2.71 Plastic Mix 3 Table 9 -The density and water absorption properties ofplastic /ilia: 3.

Compacted Bulk Density / kg in 463 Absolute Density / kg m-3 983.5±1.2 Water Absorption / 0.35 Ready-mix concrete mix designs and methods The mix designs vary to give the resulting concretes different compressive strengths. Different concrete compressive strengths are typically used for different end-uses. For example, concrete with a compressive strength of 10 MPa would be suitable for patios or pathway slabs, but not for load bearing uses such as building foundations where a stronger concrete such as 25 MPa compressive strength concrete would be more appropriate. These mix designs and methods are acting as examples but are not exhaustive.

Materials and mix designs GEM I was used as the cement. Marine sand (Hull) was used as the fine aggregates. 4-20 mm limestone obtained from Cemex oveholes) was used as the coarse aggregates. 20 mm gravel from Tarmac was used as an alternative coarse aggregate. The plastic mixes are as described in the above sections.

The mix designs are quoted as ratios (i.e., weight percentages or volume percentages) to the total mass of the concrete mix.

Table 10 -Desaiptions of the mix designs fa r the ready-mix style (entente. CC a/en-to the cement contents. The plastic and limestone percentages refer to the total mass/ vobeme of the coarse aggregate (i.e. plastic mass/ volume and limestone mass / volume), as opposed to the weight/ volume (:14) against the whole mix mass/ volume. .....

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1-001 5 wt °/0 (9 vol°,/o) plastic mix 1 95 wt°/.0 (91 vol° '0) limestone CC200 1-002 11 we/0 (18 voro) plastic mix 1,89 wt()/0 (82 volu/o) limestone, CC200 1-003 15 wt°1) (24 vol°7?) plastic mix 1,85 we), 0(76 vol°,10 limestone, CC200 1-004 19 welt, (30 vol° '0) plastic mix 1,81 wt° 0 (70 vol° 0) limestone, CC200 1-005 5 wt% (9 vol° b) plastic mix 1, 95 wt° b (91 vol° b) limestone, CC250 1-006 11 we 'lo (18 vol'io) plastic mix 1,89 wezb (82 vol" )/o) limestone, CC250 1-007 15 we'io (24 vor '0) plastic mix 1,85 wel/lo (76 vor '0) limestone, CC250 1-008 19 wt' o(30 vol" '0) plastic mix 1,81 wt°0 (70 \Tor () limestone, CC250 1-009 30 wt°/0 (44 vol° lo) plastic mix 1,70 we /10 (56 vol°/o) limestone, CC250 1-010 50 weir) (65 voln/l)) plastic mix 1,50 we 'l, (35 V01°71) limestone, CC250 1-011 75 wt° 0 (85 vol07/0) plastic mix 1,25 we'll() (15 vol°,i) limestone, CC250 1-012 5 well() (9 vol°,'"o) plastic mix 1, 95 wt°10 (91 vol°, '0) limestone, CC300 1-013 ii wt°'o (18 vol07/0 plastic mix 1,89 wt°: o (82 VOW 0) limestone, CC300 1-014 15 wt'z'o (24 volt' /o) plastic naix 1,85 wt°/0 (76 vol" 4) limestone, CC300 1-015 19 wt°'o (30 vol°/'(-) plastic mix 1,81 \X t° (70 x-ol°,"() limestone, CC300 1-016 (9 vor 4)) plastic mix 1 95 wel-'0 (91 vola/o) limestone CC350 1-017 11 wt° 0 (18 vol" '0) plastic mix 1,89 wt° 0 (82 vol0:0) limestone, CC350 1-018 15 wt" (24 V010 /0) plastic mix 1, 85 wel '0 (76 vol" ,1) limestone, CC350 1-019 19 wt°//0 (30 vol° lo) plastic mix 1,81 wt°''o (70 vol" ,/o) limestone, CC350 1-020 5 wt°10 (9 volu/o) plastic mix 1, 95 we /0 (91 vol" i0) limestone, CC400 1-021 11 etc, (18 vol%) plastic mix 1,89 W e /0 (82 V 0 r/o) limestone, CC400 1-022 15 welt) (24 vol" '0) plastic mix 1,85 we'llo (76 vor "0) limestone, CC400 1-023 9 we' 70 00 vur 70 plastic mix 1,81 we" /0 (70 \tot-Lc) limestone, CC400 1-024 5 wt% (9 vol%) plastic mix 71, 95 wt% (91 vol%) limestone CC450 1-025 11 welt) (18 voro) plastic mix 1,89 wt/0 (82 vor0) limestone, CC450 1-026 15 wt% 24 vol%) plastic mix 1,85 we, b (76 vol%) limestone, CC450 1-027 19 wt° 0 (30 vol%) plastic mix 1, 81 wt° 0 (70 vol° 0) limestone, CC450 1-028 5 wt(),/0 (9 v()1° ,''o) plastic mix 1, 95 wt0/0 (91 vc)10,10) gravel, CC250 1-029 9 wt())/0 (19 vc)10/b) plastic mix 1, 91 wt°o) (81 N-c)10,10) gravel, CC250 1-030 15 wt( Po (30 vor/0) plastic mix 1, 85 wt()/0 (70 vol()/0) gravel, (_,-C250 1-031 19 wt° l) (36 vol" /0) plastic mix 1, 81 wt°,/0 (64 vol0l/0) gravel, CC250 1-032 high water wt° "0 (18 vol° '0) plastic mix 1, 89 wt° (82 V01° o) limestone, high \ rater contents, C(250 2-001 5 wt% 9 vol',17/0) plastic mix 2, 95 wt1,/'0 (91 vol%) limestone, CC250 2-002 11 wt% (19 vol%) plastic mix 2, 89 wt% (81 vol%) limestone, CC250 1-006 1 3 1-011 1-016 1-017 Table 11 -,1111x designs p Jieicghtpercentacges of theti:02 fusented..... ... . .. * s;

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3-003 8 3 32 7 20 3-004 8 28 32 12 21 The mixes were prepared by combining the coarse and fine aggregates (including the plastics) in a pan mixer and adding half the total volume of water until thoroughly 5 combined. The cement is then added whilst the mix stirs, followed by the remaining water to give a wet concrete mix.

The slump Oyes an indication of the workability of a concrete mix. A high slump implies the mixture is easily poured, whereas a low slump indicates low workability and could cause problems when the mixture is poured. The slumps were determined using an _Abram's cone following the technique set out in BS EN 12350-2:2019. According to the British Ready-Mixed Concrete Association, slumps between 30 mm and 180 mm demonstrate that the concrete has normal to mid-range workability.

Cubes of the ready-mix concrete mixes were prepared in 100 mm molds (satisfying BS EN 12390-1:2019) and cured in water tanks as specified in BS EN 12390-2:2019.

The density of the concrete cubes was determined using the water displacement 20 method as described by BS EN 12390-7:2019.

The compressive strength of the concrete cubes was determined using methods described in BS EN 12390-3:2019 using a Matest Compression Testing Machine. Cubes were crushed at 7 days and 28 days from the date of preparation, and in the saturated state.

At 7 days, the compressive strength of the concrete should be approximately 6070% of the strength at 28 days. This means that the 7-day test can be used as an indication as to the final compressive strength of the concrete at 28 days.

Ready-mix concrete data Plastic mix 1 The slumps for the concrete mixes containing plastic mix 1 varied from 0 mm to 35 185 mm. The mean slump was 88 mm with a variance of 30 mm. The median slump was 90 mm. The highest slump of 185 mm was for mix 1-032 which was designed as a high slump mix, and the lowest slump was 0 mm for mix 1-011 containing 75% plastic replacement of the limestone coarse aggregate.

The compressive strength of the concrete varied with cement contents as well as plastic contents. As the cement contents of a concrete mix is increased, the strength of the concrete increases. The inverse is true of the increased plastic contents. For the limestone coarse aggregate samples, the compressive strength of the ready-mix concrete containing plastic mix 1 varied from 3.6 MPa to 54.1 MPa at 7 days, and from 4.5 MPa to 66.3 MPa at 28 days.

I he density of the concrete decreased with increasing plastic contents. For the limestone coarse aggregate samples, the density of the ready-mix concrete varied from 1656 kg m3 to 2415 kg m 3 at 28 days.

1 'clb/e 13 - Irady-mix cythirte mixes containing plastic mix 1 replacing limestone coarse aooreoate ITITTRIENEMEEE: Maximum 3356 Minimum 1630 Mean 2303 Standard 272 Deviation Median 2277 2415 1656 2230 144 In several samples (1-028 to 1-031 inclusive), gravel was used as the coarse aggregate instead of limestone. The compressive strength of these ready-mix concrete 20 containing plastic mix 1 varied from 12.8 N4Pa to 18.2 MPa at 7 days, and from 16.3 MPa to 23.2 MPa at 28 days.

As with the limestone samples, the density of the concrete containing gravel decreased with increasing plastic contents. For the gravel coarse aggregate samples, 25 the density of the ready-mix concrete varied from 2139 kg m-3 to 2347 kg M-3 at 7 days, and from 2147 kg m-3 to 2314 kg m-3 at 28 days.

Table 5 Density of ready-mix concrete mixe.s containing plastic mix. 1 replacing gravel coon? "reqate. gate.

Maximum. . . . . . . Minimum Mean Standard Deviation 2139 64 Median 2247 Mix 1-032 was prepared as a high slump mix (185 mm) for comparison to an equivalent mix (1-006) with a normal slump (90 mm). 'this experiment acted to mimic the addition of water to concrete mixes with a lower workability. The only difference between these mixes was the amount of water added to the mix during the preparation of the concrete. Both rnixes contain 18% by volume replacement of limestone coarse aggregate with plastic mix 1. At 28 days, the high slump mix (1032, 19.7 iN1Pa) was seen to have a slightly lower compressive strength versus the lower slump mix (1-006, 21.6 MPa) due to the addition of extra water.

Plastic mix 2 The slumps for the concrete mixes containing plastic mix 2 varied from 0 mm to 85 mm. The mean slump was 66 mm with a variance of 33 mm. The low mean was a result of the 0 mm data point skewing the data The median slump was 80 mm. The lowest slump was 0 mm for mix 2-005 containing 50% plastic replacement of the limestone coarse aggregate. The compressive strength of the ready-mix concrete containing plastic mix 2 varied from 11.9 MPa to 24.7 7\4Pa at 7 days, and from 13.1 MN. to 29.8 MPa. at 28 days.

'the density of the concrete decreased with increasing plastic contents. The density of the ready-mix concrete varied from 1875 kg 111-3 to 2354 kg 111-3 at 7 days, and from 1864 kg m-3 to 2339 kg 111-3 at 28 days.

Table 15 -Density of mady-mix: commie mixes containing plastic TJJZX 2. :

Maximum 2.354 Minimum 1875 Mean 2172 Standard 162 Deviation Median 2208 Plastic mix 3 The slumps for the concrete mixes containing plastic mix 3 varied from 40 mm to 100 mm. The mean slump was 75 mm with a variance of 22 mm. The median slump was 80 mm. The lowest slump was 40 mm for mix 3-004 containing 16% plastic replacement of the limestone coarse aggregate. The compressive strength of the ready-mix concrete containing plastic mix 3 varied from 11.8 Nll'a to 21.8 1\41)21 at 7 days, and from 14.5 N413a to 25.9 NIPa at 28 days.

The density of the concrete decreased with increasing plastic contents. The density of the ready-mix concrete varied from 2031 kg M-3 to 2306 kg tn-3 at 7 days, and from 2059 kg ITI3 to 2321 kg 111-3 at 28 days.

Table 6 -Density of ready-mix cowrie mixes containing plastic Dlix 3.

Comparison of the plastic mixes Clearly, the use of different plastic mixes results in concrete samples that vary in compressive strength and density. Error! Reference source not found, shows the compressive strength of concrete samples at different plastic replacement levels for plastic mixes 1, 2, and 3. This figure only relates to limestone replacement. From this data, it is shown that of the plastic mixes utilised in the concrete samples, plastic mixes 1 and 2 resulted in consistently stronger concrete for the equivalent plastic replacement levels than plastic mix 3. Nevertheless, all plastic mixes tested were demonstrated to successfully (partially) replace coarse aggregates in ready-mix concrete.

Concrete masonry units (blocks) mix designs and methods Different mix designs are used to create CML: products, including blocks, for different end uses. The mix designs for CMUs vary massively across the industry to give different compressive strengths, finishes, and densities of the final product. For example, two of the most popular commercially available CMU blocks are 7.3 MPa and 3.6 MPa blocks, which refers to their compressive strength. The density of a Median : : Maximum 2306 Minimum 2031 NI can Standard Deviation : 2321 2059 221)7 99 CMU Hock can be varied by mix design to gt-ve dense or lightweight Hocks suitable for different uses; a dense block is more suitable for use at the base of a building near the foundations whereas a lightweight (less dense block) can be used for building internal walls, for example, as they are not required to bear the weight of the rest of the building. Furthermore, specialty blocks with low thermal conductivities (highly insulating) or extra smooth finishes are also popular commercially. These mix designs and methods are acting as examples but are not exhaustive.

GEM I was used as the cement. limestone dust (Marshalls) was used as the fine aggregates. 4-10 mm limestone obtained from Cemex (Doveholes) was used as the coarse aggregates. The plastic mixes are as described in the above sections. Two different block mix designs were used referred to as block mix A, and block mix B. The difference between these two mix designs was the amount of coarse and fine aggregates used; block mix A contains more coarse aggregate whereas block mix B contains more fine aggregate.

The mix designs are quoted as ratios (i.e., weight percentages/volume percentages) to the total mass of the concrete mix The total volume of the concrete mix was kept 20 constant.

1 able 17 -Desaiptions of the mix designs for the semi-thy block mixes. Tibe _plastic and limestone percentages refer to the total mass/ volume of the coarse aggregate (i.e., plastic mass/ volume and limestone mass/ volume,), as opposed to the weigh// volume;1'0 against the whole mix mass/ volume.

EMEMEREMNE:: (5 \ 0100) plastic mix 1, 97 wt°0 (95 \ 010 0) coarse Bla-001 Block Mix A, 3 limestone B la-002 Block Mix A, 9 wt% (15 vol%) plastic mix 1, 91 wt% (85 vol%) coarse limestone B1b-001 Block Mix B, 3 wt':!') (5 vor plastic mix 1, 97 weE! (95 vol%) coarse limestone Block Mix A, 3 wt% (5 vol%) plastic mix 2, 97 wt°0 (95 vol limestone Block Mix limestone Block Mix A, 9 wt% (15 vol%) plastic mix 2, 91 wt% (85 vol%) coarse limestone B2a-001 B2a-002 B2a-003 ) coarse Block Mix A, 12 (20 ol°,X)) plastic mix 2, 88 wt (80 ol°,l) coarse limestone Block Mix A, 19 wt% (30 vol°,'o) plastic mix 2, 81 wt°,"0 (70 vol°,t) coarse limestone B2a-004 B2a-005 Block Mix B, 3 wt' limestone Block Mix B, limestone (5 vol%) plastic mix 2, 97 wt% (95 vol%) coarse! mix 2, 91 \ (85 or coarse B2b-001 B2b-002 9 (15 vol p1 stic (95 x Po) coarse Block Mix A, 2 wel'o (5 ol la tic m limestone Block Mix A, 7 w-tuio (15 vol%) plastic mix 3, 93 weli) limestone B3a-001 B3a-002 (85 vol%) coarse Block Mix B, 2 wt% limestone Block Mix B, 7 limestone (5 vol°, plastic mix 3, 98 \ t 0 (95 vol%) coarse B3b-001 B3b 002 (15 xo1 o) plastic mix 3, 93 wto,o (85 u) coarse 1"able 7 -Semi-thy mix dccigncpresenfed ac fi)eigbh)ercenlages et the Iola/macs (g-the mix.

Bla-001 E 9 49 35 1 B la-002 9 45 35 4 B lb-001 9 36 49 B2a-001 9 49 35 B2a-002 9 48 35 B2a-003 9 45 35 B2a-004 43 36 B2a-005 10: 39 37 B213-001 132b-002 9 B3a-001 B3a-002 9 Table 8 -Semi-thy mix designs presented as volitme percentages of the total volume of the m& 51) B3b-001 9 B3b-002 : . . . . .......

itent. :7

B1b-001 B2a-001 7 B2a-002 7 B2a-003 7 B2a-004 7 B2a-005 B2b-001 7 B2b-002 7 B3a-001 7 B3a-002 B3b-001 B3b-002 7 33 14 33 7 14 33 14 14 32 15 The mixes were prepared by combining the coarse and fine aggregates (including the plastics) in a pan mixer and adding half the total volume of water until thoroughly combined. The cement is then added whilst the mix stirs, followed by the remaining water to give a semi-dry concrete mix.

A pre-determined mass of the concrete mix was loaded in to the 100 mm cylindrical gyratory compactor mold and compressed in the gyratory compactor (Matest). The compaction parameters were as follows; internal angle 1.250°, load 5 kN, speed 60.0 rpm. The samples were compacted to a constant number of gyrations to give an approximate sample height of 100 mm.

The extruded cylinder block sample was then cured in a saturated environment 5 above a water bath at 20±2°C to provide a humid and warm environment before being removed for testing. As with the ready-mix samples, the density of the CA4lis was determined by the water displacement method (BS EN 12390-7:2019). The compressive strength of the cylindrical CA141 samples was determined using the same methods as the concrete cube samples, as described in BS EN 12390-3:2019, 10 using a Matest Compression Testing Machine. The cylindrical CM41 samples were crushed at 7 days and 28 days from the date of preparation, and in the saturated state.

Concrete masonry units (blocks) data As with the ready-mix concrete, generally, as the plastic contents increased in the CMUs, the density and the compressive strength of the CMUs decreased. Furthermore, it is suggested that the thermal conductivity of the CMUs decreased with increasing plastic contents. This is advantageous as more thermally insulating CMUs are in demand commercially and can be sold at a premium. The block mixes in these examples give dense blocks however aggregate replacement with plastic waste may also be used in lightweight blocks.

Two of the most popular commercially available CA4U blocks are 7.3 A4Pa and 3.6 NIPa in compressive strength. The compressive strength of the various mix designs described in Error! Reference source not found, range in strengths from 4.12 A4Pa to 11.1 A1Pa after 28 days of curing. The densities of the CA4U blocks ranged from 2137 kg m-3 to 2415 kg m-3 at 28 days of curing.

By changing the plastic type, the density, strength, and thermal conductivity of the 30 blocks can be varied offering a final C24U product which can be tailored to specific needs and end uses.

Compressive strength of CMUs The CA4U mixes were prepared containing up to 30% plastic replacement by volume 35 of coarse aggregate and tested. These CMUs were prepared with plastic mixes 1, 2 and 3, and to two different base block designs, block mixes A and B. Generally, the CA4U samples were tested at 1, 2 or 3 days, 7 days and 28 days. Error! Reference source not found. and Error! Reference source not found. show the compressive strengths achieved by UNIU samples made using both block designs A and B at plastic replacements of 5% by volume. These samples were seen to increase in strength with curing time.

When considering block mix A with 5% coarse aggregate replacement with plastic (Error! Reference source not found.), mix B2a-001 (made with plastic mix 2) had a compressive strength of 8.58 All'a at 28 days. This was the highest compressive strength of all the block mix A mixes containing any plastic mix at 5% replacement of coarse aggregate. When considering block mix B at 5% coarse aggregate replacement, mix B2b-001 (made with plastic mix 2) had a 28-day compressive strength of 8.48 N11)a. This was the greatest compressive strength of all the block mix B mixes containing any plastic mix at 5% replacement of coarse aggregate. These results show that for either block mix design used, plastic mix 2 gave the strongest ClAILT samples at 5% coarse aggregate replacement.

Error! Reference source not found. shows the compressive strengths of the block mixes containing 15% plastic replacement of the coarse aggregate for both block designs A and B (mixes B2a-003, B2b-002, B3b-002). At 28 days, B2a-003 (plastic mix 2) reached a compressive strength of 8.98 MPa, making it the strongest block mix-plastic mix combination for 15% coarse aggregate replacement.

Error! Reference source not found., Error! Reference source not found. and Error! Reference source not found. demonstrate that plastic mix 2 consistently 25 gave the strongest CAM samples of the plastic mix replacement coarse aggregates tested.

CMU densities Error! Reference source not found. and Error! Reference source not found. show how the density decreases with increased plastic content in the CATO samples. All the block designs tested indicated a decrease in density with plastic content. This is due to the plastic being less dense than limestone it is replacing. Furthermore, block mix B was shown to be consistently more dense than block mix A as seen in Error! Reference source not found, where block mix B was more dense than block mix A for plastic mix 2 and 3 at all plastic replacement levels tested. This was due to Hock mix B containing a higher proportion of fine aggregate, resulting in more ordered particle packing leading to greater mass fitting into the same volume.

Error! Reference source not found, shows the change in density with an increase 5 in plastic up to 30% plastic replacement by volume. This clearly demonstrates again that as the plastic contents of the mix increases, the density of the resulting CML sample decreases.

Summary of CMU compressive strength and density data Plastic mix 1 The CML block mixes containing plastic mix 1 demonstrated the lowest compressive strengths of the CMU mix designs containing plastics. The highest compressive strength at 28 days was 8.046 MPa for design B2b-001 and the lowest was 5.816 MPa for design Bla-001. Blocks made with plastic mix 1 had the highest density of the three plastic mixes.

Plastic mix 2 Plastic mix 2 was a mixture of pellet shaped plastics. This plastic geometry lent itself to use in the CMUs due to its small size which appeared to stack comfortably between the larger and smaller aggregates in the semi-dry mix. This led to more stable semi-dry mixes with repeatable strength and density values in the CMUs. Furthermore, the pellet shaped plastics in plastic mix 2 performed well in both block mix A and B. The CMU strength increased with curing time and generally decreased with increased plastic replacement of the coarse aggregates. B2a-001, B2a-002 and 112a003 were all seen to exceed 7.3 MPa in compressive strength after 28 days of curing. B2a-002 (10% plastic replacement of coarse aggregate) had the highest compressive strength at 28 days for plastic mix 2 in block mix A. For plastic mix 2, the compressive strengths at 28 days ranged from 3.213 MPa (112b-001) to 11.13 MPa (B2a-002).

Plastic mix 3 Plastic mix 3 comprised of fine flaky plastics. This meant that the plastics were conformable due to their thin film nature without being elastic. The highest compressive strength achieved with plastic mix 3 at 28 days was 8.428 MPa for mix B3a-001 and the lowest was 4.118 MPa for mix B3b-002. The CATLI samples containing plastic mix 3 resulted in the least dense block samples of all three plastic mixes tested.

Thermal performance of CMU samples Thermal tests were conducted on the CMU samples to give an indication of how thermally insulating the blocks containing plastic are compared to those without plastic. Limestone has a thermal conductivity' of 2.59 \til m-1 LC'. High-density poly(ethylene), low-density poly(ethylene) and poly(propylene) have thermal conductivities' of 0.43 W m-1 K1, 0.35 W rri-1K-1, and 0.23 W m-1K-1 respectively. It can be assumed, therefore, by changing the overall mix composition by decreasing the limestone coarse aggregate and replacing it with the waste plastic, the thermal conductivity of the resulting concrete will decrease.

An experiment to give an indication of the thermal conductivity of the CMU samples was carried out. Cylindrical CMU samples were prepared in the gyratory compactor and cured as previously described. The samples were removed from the curing tank and dried in air for a minimum of 24 hours prior to testing.

During the experiment, a hot plate was heated to a temperature of 80 °C. Thermal sensors were attached up the side of the cylindrical block sample at heights of 0 mm, 20 mm, 40 mm, and 80 mm. The thermal sensors were connected to an OMEGA data recorder connected to a computer and recorded the temperature at the position on the block at one second intervals. The experimental set up is given by Error! Reference source not found.. The block sample was placed on and left in contact with the plate for 30 minutes. The temperature of the concrete block sample at the probe locations were measured across the whole 30-minute experiment giving a temperature vi time plot. The temperature change from the start of the experiment (T0) vs the temperature at a predetermined time point (Tt) was calculated for each probe position (Eq. 1).

dT = Tt -To Eq./ The temperature change from To to the temperature at 500 seconds, 1000 seconds, and 1500 seconds (T500, 7io0o, and 71500 respectively) at each of the probe positions up the block sample were plotted on a graph of temperature difference against issEjum, at a., 21.,:z0102 Con6S.72F.:Mr-Iter SciEr8. 86::: 012014 'A. Poonyalcan, at al. Materials, 2018, 11, p.1938.

distance (from the base of the sample). Error! Reference source not found. illustrates an example of such a plot.

The parameter of interest from these plots was the gradient (dT/dx) as this showed 5 how the temperature changed over the distance up the block from the heat plate. The mean gradients of the linear fits of the distance versus temperature difference plots (dT/dx) were taken as an indication of thermal performance. The mean dT/dx was calculated across the three time points from each plot. Each block sample was tested multiple times so that a mean dT/dx could be obtained for each block sample. 10 The standard deviation about the mean was also calculated.

From Error! Reference source not found., it can be seen that the gradients of the linear fits are negative. A more negative dT/dx indicates a greater temperature change versus distance across the block sample. This signals that a CATE block sample with a more negative dT/dx has a lower thermal conductivity and be more thermally insulating. Error! Reference source not found. and Error! Reference source not found, show dT/dx data for block mix A and block mix B, respectively, as a function of plastic replacement by volume for each plastic mix tested.

BS EN 1745:2020 states that for blocks containing no waste aggregate, the thermal conductivity is impacted by the volume of the block; therefore dT/dx for each CAR: sample was plotted against density (see Error! Reference source not found. and Error! Reference source not found.). These figures demonstrate that as the density increases, dr/dx becomes more negative, suggesting the thermal conductivity decreases with decreasing density. Since the density of the blocks was seen to decrease with an increase in plastic replacement, it is suggested that by increasing the plastic replacement in the blocks the thermal conductivity of the blocks will decrease. Furthermore, the use of plastic as a replacement to limestone will further reduce the thermal conductivity as the plastic has a significantly lower thermal conductivity than the limestone.

From the full range of data collected on CNIU blocks containing plastic waste materials as a partial coarse aggregate replacement, it has been demonstrated that all plastic mixes tested can successfully partially replace coarse (limestone) aggregates in CMUs.

l'able 9-Fail slump, compressive strem,db, and density data set JO r the ready-mix concrete * ixes.

1-001 1-002 1-003 1-004 12.2 2214 10.2 3183 14.5 11.8 1-005 1-006 30.5 21.6 24.4 2306 17.6 2246 1-007 1-008 1-009 1-010 1-011 18.5 17.6 10.0 1().1 3.6 2186 35.6 2171 2025 1895 1630 () 9(1 28,8 2251 23.3 2191 1-013 1-014 34.4 27.6 1-015 2191 2181 2034 1893 1656 2330 2279 2190 2181 34,3 2286 27.6 52.7 41.5 -35.4 31.6 45.2 335(I 36.3 2280 30.3 2251 27.2 22( )3 1-016 1-017 1-018 1-019 60.4 42 8 41.9 1-020 1-021 1-022 34.7 28.9 2207 1-023 1-024 54.1 2349 1-025 38.9 2298 45.7 38.8 2274 1-026 46.4 1-027 1-028 1-029 1-030 1-031 2314 2276 2209 2147 43.5 5(13 28 39.4 38.5 32.4 2193 95 110 95 2347 2290 2203 2139 1-032 185 16.4 2257 19.7 2-001 85 24.7 2354 29.8 2-002 85 22.4 2261 26.0 2-003 80 19.4 2208 23.2 2-004 80 16.4 2160 19.7 2-005 0 11.9 1875 13 1 3-001 100 21..8 2306 25.9 3-002 80 20.9 2247 24.5 3-003 80 15.2 216.' 19.3 3-004 40 11.8 2031 14.5 2339 2275 2233 2156 1864 2321 2265 2181 2059 Table 10 -Fall slump, compressive strength, and density data setlOr the semi-thy CAViL concrete : 7.509 2411 n; a 2377 8.046 2407 7.509 2411 2343 6.484 2415 5.799 2342 6.617 2137 5.848 2406 -7.372 2370 7.859 2356 n"/ a 2228 6.843 2384 4.118 2278 Blia-001 6.752 2405 Bla-002 ni a 2331 B2a-001 6.373 2424 B2a-002 9.641 2329 B2a-003 7.590 2333 B2a-004 4.999 2355 B2a-005 6.642 2149 B2b-001 2.634 2424 B2b-002 3.552 2412 B3a-001 6.625 2337 B3a-002 n/ a 2252 B3b-001 8.573 2684 B3b-002 3.05 2268 Using non-packaging waste plastic in the invention, the required UK standards at present Tf the plastics material used in the aforementioned invention are waste plastic 5 materials, at present in the UK, the waste plastics should be recycled conforming to the following standards; BS EN 1543:2007, BS EN 15374:2007, CEN/TR 15353:2007. These are subject to change at any time.

These standards form part of series of GEN publications on Plastics Recyclingwhich is structured as follows: * EN 15342, Plastics -Recycled Plastics -Characterization of polystyrene (PS) recyclates * I Ai 15343, Plastics -Recycled Plastics -Plastics recycling traceability and assessment of conformity and recycled content * Id\I 15344, Plastics -Recycled Plastics -Characterisation of Polyethylene (Pk) recyclates * EN 15345, Plastics Recycled Plastics Plastics recyclate characterisation of (PP) recyclates * EN 15346, Plastics -Recycled plastics -Characterisation of poly(vinyl chloride) (PVC) recyclates * EN 15347, Plastics -Recycled Plastics -Characterisation of plastics wastes * EN 15348, Plastics -Recycled plastics -Characterization of poly(ethylenc terephthalate) (PET) recyclates * CEN/TR 15353, Plastics -Recycled plastics -Guidelines for the development of standards for recycled plastics By following these standards, the invention and products made therefrom complies to the following: * Generates a lower environmental impact than alternative recovery options by using the plastic waste as a substitute for raw materials such as gravel /limestone.

* By recycling the plastic waste there is a reduction in waste being sent to land fill or incineration at minimum costs to society.

* Upon mixing the plastic waste with the conventional aggregates, the resulting product requires no further treatment before use in the invention.

As a further demonstration of the commercial viability of the invention, a CE mark has been obtained on the coarse aggregate mixture containing plastics (19 by mass plastic waste, 81 % 4 -20 mm limestone mix) through a U K AS accredited laboratory against BS RN 12620:2002+A1:2008 in line with the requirements of BS EN 8500:2015+A2:2019 and BS IN 206:2013+A2:2021 so the aggregate mix can be used in concrete commercially. Table 22 shows the BS EN 12620 characterisation of an example 19% by mass repurposed waste plastic and 81% 4-20 mm limestone aggregate mix.

Table 22 -BS EN 12620 characterisation of anexample 19?/ by mass repurposed waste plastic and 81% 4-20 mm limestone trggregate mix Oven Dried 264 Mifirli ni iticie Density tiferiterrit Apperdet Aparepete 4bradivri Valet, (4AV) 14 Camped:de 3E3ik Dimsity 1.22 Coeffideni itA) 25 Merteeende St:innate Steisretens Sdeid1St Water Scidisle Stinsnase d SAy.&24bLSeetth424y..

Totel ditiphur eQ.1 *i-ceitrbie-rtP5%.<*.

Diying Shrinkage: 0.055 Alcticti

Claims (29)

1. Clatnas 1. A concrete formulation, said formulation including at least one aooregatc and a 5 binder, characterised in that the aggregate includes plastics material said plastics material including two or more of the following; - Poly (ethylene); Poly (ethylene terephthalate); Poly(propylene); Poly (styrene); Poly(vinyl chloride); Nylons; - Poly(lactic acid); Rubbers; and - copolymers of the above.
2. 2. A concrete formulation according to churl. 1 wherein the concrete formulation is suitable for ready mix concrete and products made therefrom.
3. 3. A concrete formulation according to claim 1 wherein the concrete formulation is suitable for concrete masonry units and other similar products.
4. 4. A concrete formulation according to claim 2 wherein the aggregate includes coarse aggregate and fine aggregate and at least part of the bulk or coarse aggregate 25 comprises at least two or more of the plastics from the list; Polyethylene (PE); Polyethylene terephthalate (PET); Polypropylene (PP); - Polystyrene (PS); Polyvinyl chloride (PVC); Nylons; - Polylactic acid (PLA); Rubbers; and - copolymers of the above.
5. 5. A concrete formulation according to claim 1 wherein the plastics material is recycled and/or recovered plastics material.
6. 6. A concrete formulation according to claim 5 wherein the plastics material is recovered waste plastics material.
7. 7. A concrete formulation according to claims 6 wherein the binder is a cementitious binder or cement.
8. 8. A concrete formulation according to claims 1-6 wherein the binder includes, or comprises, a non-cementitious binder.
9. 9. A concrete formulation according to claim 6 wherein the plastic waste material is sourced from waste reprocessing sites.
10. 10. A concrete formulation according to claim 9 wherein the plastic waste is processed to include of pellet, chip, or Bake shapes or a mixture thereof
11. 11. A concrete formulation according to claims 4-10 wherein the processed plastic 20 waste may replace up to 100 of the coarse aggregate in concrete.
12. 12. A concrete formulation according to claim 13 wherein the plastics material forms 1-75% by weight (1-85% by volume) of the coarse ao-oregate.
13. 13. A concrete formulation according to any preceding claim 9 wherein the plastics material includes polymer pieces a minimum of 10 microns in diameter.
14. 14.A concrete formulation according to claim 13 wherein the size is substantially 1-20mm in diameter.
15. 15. A concrete formulation according to claim 14 wherein the si2e is 4-70mm in diameter.
16. 16. A concrete formulation according to claims 10-15 wherein the pellets are 35 between 2.00 mm and 4.60 mm in their longest dimension.
17. 17. A concrete formulation according to claims 10-16 wherein the chips possess one longer axis with two shorter, said chips being between 3.0 mm and 190 mm in their longest dimension and between 16.0 min and 0 5 mm in length in the two shorter dimensions.
18. 18. A concrete formulation according to claims 10-16 wherein the flake shaped plastics are substantially two-dimensional with each piece being significantly thinner in one dimension than the others, the thickness of the flakes is between 0 05 mm and 4.2 mm.
19. 19. A concrete formulation according to claim 18 wherein the flake width is between 1.0 mm and 10 mm
20. 20. A concrete product poured or formed from a formulation according to any 15 preceding claim.
21. 21. A concrete product according to chim 20 wherein the product is an interlocking concrete block.
22. 22. An interlocking concrete block according to claim 21 wherein substantially 9, 12 or 15 Y0 weight of the aggregate is plastics material.
23. 23. An interlocking concrete block according to claim 21 wherein the plastics material forms around 5-19 % by weight of the coarse aggregate material.
24. 24. A method of preparing ready mix concrete, said method including the steps of replacing at least some of the aggregate with a combination of plastics material selected from two or more of polystyrene (PS), low density polyethylene (LOPF;), high density polyethylene (H DPI other polyethylenes (P1), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyamides (including Nylons and other related polymers), and/or polyesters and/or co-polymers thereof.
25. 25. A concrete masonry unit (C N4 U), wherein said CM U includes substantially 1-19 % by weight (1-30% by volume) of the aggregate material is plastics material.
26. 26. A CMT: according to claim 25 wherein the CML1 contains at least two of the following plastics; polystyrene (PS), low density polyethylene (LOPE), high density polyethylene (H D1)11), other polyethylenes (P11), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyamides (including Nylons and other related polymers), and/or polyesters and/or co-polymers thereof.
27. 27. A CMU according to claim 26 wherein the CME the plastics material forms substantially between 3-19 °,710 weight of the aggregate of the mix forming the CMU.
28. 28. A CATE according to claims 25-27 wherein the plastics material is 2-10 mm diameter for semi-dry concrete mixes from which CiMU is prepared from.
29. 29. A LIME according to claims 25-28 wherein the plastics material can replace coarse aggregates up to 19% by mass.